Yes, x-ray scanners seem to of made big inroads and only recently I learned that companies use them to verify phones as in the past they would visual check them

Yes, x-ray scanners seem to of made big inroads and only recently I learned that companies use them to verify phones as in the past they would visual check them - but copies have gotten so good that xray is the only real way now. Though even then, you have to have something to compare it with and also know what you are looking at and able to eliminate what should and shouldn't be there. Though when you have multilayer flash, the possibility to have a nefarious layer, sandwiched between good layers, makes things way harder. All that said, as a rule, I'd just downright ban any non-company/entity USB drive or any tech. Keyboards and Mice, more so.